getServers

setServers

Set the list of DNS server addresses, an address is the IP of the dns server, followed by an optional
colon and a port, e.g 8.8.8.8 or {code 192.168.0.1:40000}. When the list is empty, the resolver
will use the list of the system DNS server addresses from the environment, if that list cannot be retrieved
it will use Google's public DNS servers "8.8.8.8" and "8.8.4.4".

getCacheNegativeTimeToLive

setCacheNegativeTimeToLive

Set the negative cache TTL value in seconds. After a failed hostname resolution, DNS queries won't be retried
for a period of time equals to the negative TTL. This allows to reduce the response time of negative replies
and reduce the amount of messages to DNS servers.